The following use of apostrophe is correct.

Gita is Sita's sister.

But suppose Sita is name of two twin sisters and Gita is their younger sister. So how should we write that?

1) Gita is Sitas' sister.


2) Gita is Sita's sister.

It seems to me, that in certain cases, the apostrophe comes after the s, though I might be wrong.

  • ell.stackexchange.com/questions/10558/…
    – user230
    Sep 23, 2013 at 14:33
  • @snailboat, Thanks to point out. I did not see it. So I voted to close this question as a duplicate.
    – Mistu4u
    Sep 23, 2013 at 14:41
  • More help/guidance is available at the Purdue OWL, too.
    – J.R.
    Sep 23, 2013 at 14:53
  • 2
    I think that 10558 is related, but not a duplicate. Apostrophe rules can change depending on whether or not the plural word ends with 's'. Even though the answer there addresses more than one issue, that other question specifically asks about a plural noun that doesn't end in 's', this one asks about a proper noun that does.
    – J.R.
    Sep 23, 2013 at 15:04
  • @J.R. Since this showed up in the re-open queue: As I understand it, standard network-wide policy is to close as a duplicate if a complete answer to the question is elsewhere, leaving the duplicate as a signpost. Snailboat's answer on the linked duplicate completely answers this question, even if the questions are not exact duplicates. Oct 1, 2013 at 20:44

1 Answer 1


You are kind of right.

The apostrophe comes after the "s" when the "s" is part of the word. This includes plurals ("the dogs' bone") as well as non-plurals that happen to end in "s", eg, "Mr Davis' daughter", "the bass' strings" (as in, a bass guitar).

The problem is that, in English (I don't know about other languages/cultures), you would generally not have sisters with the same name - if you did, you would have to explain that in your answer. So in this particular instance, while "Gita is Sitas' sister" is grammatically correct, your exact meaning would not be understood without the extra information, which in most cases would be done with rephrasing: eg, you could say "Gita is the sister of the Sitas (they are twins with the same name)". If the person to whom you are speaking already knows of the unusual case of the twins with the same name, then they probably would understand "Gita is the Sitas' sister" (you would need to add "the" to avoid confusion with "Sita's" singular).

As an aside, you may sometimes see " 's" after an "s", as in "Mr Davis's daughter". This is the same as just the apostrophe ("Mr Davis' daughter"), but old-fashioned use.

  • 2
    Old-fashioned? That's up for debate. For anyone looking to root out the "right" answer, I'd recommend further reading, such as Daily Writing Tips or Grammar Girl's column on the subject. This one is still confusing for a lot of people. Sometimes, even the style guides don't agree. More good stuff here, too.
    – J.R.
    Sep 23, 2013 at 14:58
  • Good point that it depends on the style to which you adhere. It seems to me that the practice of using 's after an s does seem to be losing favor though, nowadays.
    – nxx
    Sep 23, 2013 at 19:09

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